Coherent self-homodyne detection (SHD) in spatial division multiplexing (SDM) systems is based on transmitting a pilot tone (PT) in one spatial channel and distinct signals on the remaining spatial channels. SHD requires that the PT and signals originate from the same light source and are phase coherent. After transmission through a spatial division multiplexing media, the signals are received using coherent homodyne detection with the PT as local oscillator (LO). As the signals and PT are phase coherent at the receiver input, the impact of laser phase noise from the original light source in the detected signal after optical-to-electrical conversion is cancelled. As a consequence, SHD allows the use of low-cost wide-linewidth lasers, it does not require carrier frequency offset estimation or compensation and requires only residual phase noise compensation. In the case of digital receivers, this greatly simplifies the required digital signal processing, lowering cost and energy consumption of the receiver. In addition, SHD does not require the use of a potentially costly laser to be used as local oscillator at the receiver. SHD may be used in any form of existing spatial division multiplexing media, such as multi-core fibers, multi-mode fibers, hybrid multi-mode and multi-core fibers, independent fibers or multi-element fibers.